How Accurate Are Gender Ultrasounds? Stats & Insights

Are you too excited to wait and discover the sex of your baby at birth? Then read on.

Let's discover more about gender ultrasounds (where “gender” refers to baby’s sex) including how they work and how accurate they can be.

What are gender ultrasounds?

These scans have become a regular prenatal test that uses high-frequency sound waves to create images of your developing baby inside your womb!

What Happens During the Ultrasound

During the examination, a sonographer uses an ultrasound machine to check the genital area of the baby for specific markers. These markers could be the presence or absence of a penis or labia.

If these markers are apparent, the sonographer can determine the baby’s sex.

How accurate are they? 

Gender ultrasounds are typically reliable and have an accuracy rate of approximately 95% to 99% when done after the 16th week of pregnancy. However, different factors can affect the precision of the results, such as the timing of the ultrasound, the position of the fetus, the size of the mother's body and the existence of multiple pregnancies.

What impacts the accuracy of ultrasounds?

Timing

The accuracy of predicting the gender of your baby through an ultrasound can be affected by the timing of the scan. Usually, the results are more reliable if the ultrasound is done later in the pregnancy.

Positioning

The position of your little one during an ultrasound can affect the image quality and make it a bit tricky to determine their gender accurately. No need to worry, though - your healthcare provider will do their best to get a clear picture!

Your body size

Determining the gender of a baby through ultrasound images can be affected by the mother's body size and shape. Ultrasound probes emit soundwaves that penetrate many body layers to reach the uterus and the baby. 

However, as the baby is moving around in a sizeable fluid-filled sac, it can be challenging to identify the baby’s gender accurately.

Pregnancy with multiples

Identifying the gender of babies in multiple pregnancies can be complicated. The more babies you have in utero, the more difficult it may prove to determine the sex. 

Can an ultrasound be wrong about baby’s sex?

Gender ultrasounds have a small margin of error due to factors like the baby’s positioning, timing, and the skill of the sonographer. They usually follow up with a statement such as, “But don’t go painting the room pink/blue, just in case.”

Can a boy look like a girl on an ultrasound?

In some cases, the appearance of the genitalia on an ultrasound can be influenced by various factors, leading to misinterpretation. This can result in instances where a boy may appear to have female genitalia on the ultrasound image.

When does a gender ultrasound take place?

During your second-trimester anomaly scan, also known as the 20-week scan, the sonographer can usually determine the gender of your baby. However, it's important to note that this is not the primary purpose of the scan. 

The main goal of the scan is to examine all the structures in your baby's body, including the heart, brain, kidneys, and lungs, to ensure that your baby is healthy. If you wish to know the gender at this appointment, simply ask the sonographer to check out the baby’s genitalia.

How do I prepare for a gender ultrasound?

If you're preparing for a gender ultrasound, make sure your bladder is comfortably full to help obtain clear images. Wear comfortable clothing that allows easy access to your abdomen. 

Also, be prepared to discuss any questions or preferences with your healthcare provider.

The Nub Theory

It's interesting to know that the Nub Theory is a method that some parents use to predict the gender of their baby. This theory is based on the angle of the genital tubercle, a small bump that develops in early pregnancy. 

However, it's important to note that this theory is not foolproof and it's always best to confirm the gender with a medical professional during a routine ultrasound.

What other ultrasounds can I expect?

You may need to undergo several ultrasounds during pregnancy to monitor the baby's development and ensure a healthy pregnancy. The dating ultrasound is usually done around 8-14 weeks to estimate the due date. 

The anatomy ultrasound is performed around 18-20 weeks to check the baby's growth and development, as well as the placenta, amniotic fluid, and umbilical cord. The growth ultrasound is done later in pregnancy to check the baby's size and position. 

Your healthcare provider will guide you on when to expect these ultrasounds and what to expect during each one.

Useful Links:  

What-to-know-ultrasound-babys-sex

What's the Chance Baby's Gender Test Is Wrong?

Gender Ultrasound: Are You Having a Boy or Girl?


Written By: Midwife Laura

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